À la base le groupe est composé d'ex-membres de Minor Threat et de Bloody Mannequin Orchestra. Au cours de ses quatre années d'existence, le groupe connaîtra d'incessants changements de lineup. Ainsi Dag Nasty sera la terre d'accueil de futurs membres de groupes prestigieux (Descendents, Bad Religion, Down By Law...). On parle souvent de Dag Nasty comme du pionnier du mouvement punkcore mélodique. En effet, le groupe est caractérisé par des sonorités plus mélodiques et accessibles que celles de groupes comme Black Flag ou Minor Threat par exemple.
↑(en) Steven Blush, American Hardcore : A Tribal History, New York, Feral House, , 333 p. (ISBN0-922915-71-7), During the 'Revolution Summer' of '85 many harDCore types reinvented themselves. 'Emo,' for emotional post-Hardcore, described the move to softer, more emotive music, embodied in Ian [MacKaye]'s project Embrace, Brian Baker's Dag Nasty, Thomas Squip's Beefeater, Kingface with Mark Sullivan, Bobby Sullivan's Lunchmeat, and Rites of Spring with Guy Picciotto and Eddie Janney.
↑(en) Greenwald, p. 14. Ian Mackaye was such a huge Rites of Spring fan that he not only recorded what was to be the band's only album in 1985 and served as a roadie for them while on tour, but his own new band, Embrace, explored similar themes of self-searching and emotional release. Other peers followed suit, including Grey Matter, the archly political and arty Beefeater, and Fire Party, whom Jenny [Toomey] termed 'the world's first female-fronted emo band.
↑(en) Brian Cogan, The Encyclopedia of Punk, Sterling, , 66–67 p. (ISBN978-1-4027-5960-4).
↑(en) Thomas Erlewine, « Dag Nasty », Allmusic (consulté le ).